I've been looking for a 2.5" small HDD for a while, too. Bought one 207MB drive from a radio rally - Never worked. Bought a IBM Travelstar 4.86GB for £5 - Click of death.
I have a spare laptop drive, but its a Quantum Go Drive 42.9MB SCSI-II - So not much use.
I've also got a Toshiba laptop with a HDD, except the drive keeps on going clunk...clunk...clunk... so its probably not very well.
I'd also say save the low capacity 2.5" drives. I've got a stack of IDE ~2GB drives, except that they are all 3.5". A bit difficult to mount in A1200's or A600's.
Hodgkinson.